Even though every plant species has an inbuilt unique chemical complex structure that protects it from/provides resistance against pests/insects; there remains a need for external pesticides that will protect the plant against those pests which are resistant to inbuilt resistance of plant.
Currently, synthetic insecticides are used to protect stored grain/seed from insect infestation. Synthetic insecticides are manufactured at least in part using synthetic chemicals created from other chemicals. Synthetic insecticides are undesirable because of ecological and toxic effects of the chemicals. They are not permitted for use on organically produced grain/seed. The continued use of synthetic insecticides has led to a large number of insect pests developing resistance to the insecticides. As a result, these insecticides have to be withdrawn or larger quantities need to be used, exacerbating the problem. The problem of insect resistance is also indicated with Bacillus thuringiensis, the most widely used and intensively studied microbial insecticide.
Biopesticide offer an answer to the above problems, as they are eco-friendly, non-persistent, safer to use and the chances of insect pests developing resistance is unlikely as the insecticidal activity is normally due to multi-component active ingredients.
Thus, alternative to synthetic pesticides are pesticides derived from natural materials such as animals, plants, bacteria, and certain minerals.
Preferable, biopesticides are natural plant products that belong to the so called secondary metabolites that include thousands of alkaloids, terpenoids, phenolics and minor secondary metabolites. Biopesticides have usually no known function in photosynthesis, growth or other basic aspects of plant physiology; however, their biological activity against insect pests, nematodes, fungi and other organisms is well documented.
Reference may be made to the use of plants and minerals as traditional protectants of stored products, wherein the traditional method of mixing sand with stored grain is documented. However, since the sand particles are used to block the inter granular spaces and act as a physical barrier to the movement of insect pests, large quantities of sand have to be used which is unhygienic and also necessitates sieving off the sand before using the grain. [Golob, P and Webley, D. J., (1980) G138, Chatham, UK, Natural Resources Institute]
The use of diatomaceous earth based formulations for the protection of stored grain in the USA and Australia is documented. However, the drawbacks are that the treatment inhibits the free flow of grain and also damages grain handling equipment. More recently, health problems to workers have restricted its use considerably. [Frank H. A., Grain protectants: Current status and prospects for the future, J. Stored Prod. Res. 32(4)293-302 1996]
Use of mineral dusts for protection against insect pests with special reference to cereal grains, in Grain Sanitation wherein activated clay is used as a nontoxic grain protectant is documented. [Eds. S. K. Majumder & J. S. Venugopal, Academy of Pest Control Sciences, Mysore, India, 1969, pp. 81-96]. Diatomaceous dusts have also been used as grain protectants. However, the treatment is not effective on grain with high moisture content or in regions with high relative humidity as in coastal areas as reported by Mevis I, Ch. Ulrichs (2001), J. Stored Prod. Res. 37. pp. 153-164. Action of amorphous diatomaceous earth against different stages of the stored product pests Triboliumconfusum, Tenebriomolitor, Sitophilusgranarius and Plodiainterpunctella are also disclosed.
Reference may also be made to Studies on plant oils as surface protectant against pulse beetle Callosobruchus chinensis (L.) in chickpea, Cicer arietinum L. [Singal, S. K. and Singh. Z, 1990, Tropical Pest Management, 36.314-316] wherein the traditional practice of mixing stored grain with vegetable oils is documented. However, the drawbacks are that the oils apart from being expensive also turn rancid and may impart an off-flavour to the grain as shown by Pereira, J. and Wholgemuth, R. 1983, J. Stored Prod. Res. 19, 57-62. The effect of six vegetable oils as protectants of cowpeas and Bambara groundnut against infestation by Callosobruchus maculatusis also reported.
References may be made to Journals Efficacy of deltamethrin against storage insects in rice and wheat under FCI's storage system. (Pesticides pg 39-43) and toxicity of deltamethrin, chlorpyriphos, methyl etrifos, malathion and fluvalinate against Sitophilus oryzae and Trogoderma granarium. Ind. J. Ent. 56(4). 322-325 by Yadav et al., wherein the organophosphate insecticide DDVP is used in insecticide formulations along with malathion for the control of insect pests in grain storage. However, insects have become resistant to DDVP and malathion and these are being phased out. DDVP is known to be carcinogenic. Currently, while malathion is being replaced with deltamethrin, there is no replacement for DDVP which acts in the vapor phase.
References may be made to patents IN192851 and IN199867 by Pereira et. al. describe a process for the preparation of a formulation useful for the insect free storage of cereals using roots of Decalepis hamiltonii Wight. and Arn. and its extracts mixed with substituted phenols wherein substituted phenols were mixed with the dried root powder/solvent extracts of the roots of Decalepis hamiltonii to provide a stable, synergistic formulation for the storage of insect free cereals. However, the formulation is not effective against the red flour beetle, Tribolium castaneum Herbst. There is need to develop new insecticides of biological origin (biopesticides) that are biodegradable and do not leave residues, which are also species specific and do not harm non target organisms.
Nothapodytes nimmoniana (Syn: N. foetida, Mappia foetida) (Family: Icacinaceae) is gaining international importance due to their pharmacological and curative properties. The wood-extract of this tree is used in the treatment of cancer. It is believed that Camptothecin (CPT) is the third most important alkaloid sought after by the pharmaceutical companies around the world. Few developments on pesticide/herbicide and insecticidal properties of Nothapodytes nimmoniana extracts are enlisted in below references:
References may be made to patent JP61200902, provides a novel herbicide containing 9-methoxycamptothecin, etc., extracted from vegetables as active components, exhibiting excellent herbicidal effect to various weeds and free from phototoxicity to important crops such as corn, wheat, rice, soybean, cotton, etc. The said herbicide contains, as active component, 9-methoxycamptothecin separated from Mappia foetida (a plant of Icacinaceae family) and reported to have carcinostatic and antileukemic activities, or an extract containing 9-methoxycamptothecin extracted from a plant.
The extraction of the above active component is carried out by conventional process for the extraction of natural component, e.g. by the extraction with an organic solvent such as methanol, acetone, ethyl acetate, etc., following concentration, etc. The herbicide is effective against broad-leaved weeds such as white-bird's-eye, smooth pigweed, green amaranth, etc., gramineous weeds such as barnyard grass, green foxtail, etc., cyperaceous weeds such as yellow-cyperus, etc.
References may be made to U.S. Pat. No. 6,893,668 (corresponding Indian Patent Application No. 746/DEL/2003) provides a process for the isolation of Camptothecin from the twigs and stem of N. foetida, which comprises of drying, grinding N. foetida twigs and stems, subjecting the dried and ground N. foetida twigs and stems to hot defatting with a light petroleum fraction followed by successive sequential hot extraction with two solvents, removing the solvents under vacuum to obtain crude extracts of the plant material, precipitating and filtering the crude plant extracts to obtain Camptothecin with up to 0.15% yield.
References may be made to patent CN101243796 (WO2009/111950) which relates to a composition of pesticide and the manufacturing method, belonging to botanical pesticide which is characterized in that the composition comprises an active constituent with 0.1 to 2.0 percent of the total weight. The constituent is single compound or the mixture of compounds which accords to the general formula I, wherein R1 is Na and R2 is H or OH.

The composition of pesticide adopts the ring opening camptothecin salt as the insecticidal active compound, wherein, the camptothecin salt is high in activity and can be dissolved in water.
References may be made to patent US20020018762 relates to insect control with Camptotheca products, particularly, termiticides, baits, preservatives, and termite-resistant products. Natural or synthetic Camptothecin and/or one of its natural or synthetic analogs are applied to deter and/or eliminate termites, while flavonoids are applied to attract termites. CPTs and/or CPTs-containing plant matter is processed with cellulose products to produce termite-resistant products and structures.
Further “Insecticidal Activity of Camptothecin against Nilaparvata lugens, Brevicoryne brassicae, and Chilo suppressalis” by Jianyi Ma, et. al. discloses that greenhouse tests showed that 0.2% Camptothecin Emulsifiable Concentrate (EC) has strong contact toxicity to three agricultural pests in the following descending order Nilaparvata lugens Stahl, Brevicoryne brassicae L., Chilo suppressalis Walker.
Camptothecin isolated from the stem of Nothapodytes foetida is known to possess anti-cancer properties, which is currently in demand for anticancer treatment. Therefore, the present inventors have evaluated the Nothapodytes foetida stem extract that is substantially free from camptothecin for its other biological activities and surprising found that the stem extract of Nothapodytes foetida is found to be an effective biopesticide for the insect free storage of stored grain and seed.
Accordingly, the present inventors have developed a biopesticide from the stem of Nothapodites foetida, that can be used to protect stored grain/seed and also store organically produced grain/seed from insect infestation. The said biopesticide being of biological origin is eco-friendly and less toxic to non-target organisms.